Margaret Hodge has had a long and chequered career as a politician. Council leader, MP and Labour minister, at 68 she looks like ending it on a high, as an activist and effective chairman of the powerful Commons public accounts committee (PAC). So when she tells Monday's Guardian that parliament risks looking "lazy", we should sit up and take notice.

What exactly is Hodge complaining about in her interview with Rajeev Syal? It's not that individual MPs are lazier. As with most people the pressure of modern life – not least the internet and 24/7 communications – makes them work harder than ever. There are lazy ones, but then lazy voters deserve proper representation too.

I think Hodge mainly means that the Commons itself does not sit as often as it used to do – just below 140 days in the current parliamentary year, more normally about 150 days: part of a gentle downward curve over the decades as you can see in this research paper. Beware: election years look short and the session that follows a spring election is usually very long.

The knock-on effect from that is what worries the PAC chairman, ex-Islington council leader and MP for Barking since 1994, because select committees like hers, which do the fundamental job of holding the executive branch of government – ministers – to account (bankers too), cannot sit on days when parliament is not sitting too. The volume of work grows as arms-length quasi-government agencies grow in number and need to be questioned in public about their varying performance.

But there are deeper problems and forces at work here, some specific to the coalition, others arising from big government trends over recent decades, not least during the rule of that famous enemy of big government, Margaret Thatcher, who centralised quite a lot of things under the banner of making them "free".

As Hodge (strictly speaking she's Lady Hodge since her late husband, the civil liberties lawyer Henry Hodge, ended up a high court judge and knight) explains in the Guardian, part of the problem is that the coalition disagrees about so much that it is short of legislation to push through parliament. That's not necessarily a bad thing since hyperactive legislation (much of which doesn't work or isn't even implemented) is a vice of the age. And yes, Mrs T did plenty of it too.

But it means that where Lib Dems and Tories disagree, stuff gets kicked into the long grass of consultation or commissions. Equally important, where the coalition knows it faces problems with the half-reformed House of Lords – where no party now ever has a majority – it has to box and cox. One dodge it uses is to start legislation at the Lords end of the building because by doing so they identify and hopefully iron out major problems before they reach the Commons.

That unbalances the legislative programme, leaving backbench MPs kicking their heels while the Lords – whose bills cannot be forced to meet a timetable "guillotine" as the Commons now can – ruminate over details great and small. I'm a fan of the current Lords, without the old Tory numbers bias but with all the biases that wide-ranging experience, old age and a lack of personal ambition bring to an issue.

The reassertion of backbench power in the wake of the expenses scandal means that ordinary MPs are wresting back some control of their own agenda from the whips of both parties who like to control things – see This House, the 70s play now running at the National Theatre. One benefit has been that backbenchers now vote on who shall chair select committees, so that knowledgeable and independent-minded people like the Treasury committee's Andrew Tyrie – scourge of the banking classes – and indeed Hodge herself get jobs the whips once preferred to give to malleable loyalists.

So some of that spare time is taken up by backbench-inspired debates, designed to highlight issues or even select committee reports – and put the government on the spot, as Tory MPs like to do over Europe, taxes or local planning reforms. It's good stuff and I think the 2010 intake of new brooms is proving to be a good parliament in difficult times – not least the anti-politics mood of know-nothing populism which characterises much commentary in shameless Fleet St and the social media.

But the odds have been stacked against backbenchers by reforms agreed by whips on both sides in and out of government over the past three decades, procedural and other changes designed to make things easier for the sitting regime in Whitehall to manage the legislators across the street. That's why I thought it healthy that rebel MPs and peers forced the three main party leaders to cut a midnight deal on the Leveson press reforms – even though the details of the deal still need a lot work to safeguard both press and public interest.

The higher turnover of MPs these days makes it easier for governments to bend the rules because there are no bloody-minded backbench procedural experts like Labour's Tam Dalyell or the late Tory MP Robin Maxwell-Hislop, lying in wait to call their bluff. Both could be a confounded nuisance but were essential figures. Great Tam's wonderfully self-aggrandising autobiography is called The Importance of Being Awkward.

The coalition's procedural devices include rescheduling days at short notice – ministers last caused a row over the budget, prompting a disruptive Labour challenge.

There is also an awkward trend whereby Lords and Commons don't sit on the same days. That means less inter-activity and collegiality, itself gravely weakened by Labour's embrace of "family-friendly hours" – ie, the 9-to-5 view.

It has its advantages and its supporters. But parliament's limbs atrophy if not exercised, just as individuals' limbs do, and it saddens me to see the Palace of Westminster, once bustling with life late into the night, now often silent and deserted. The change does not seem to have improved the divorce rate, as we were piously told it should.

There is another problem. The old Victorian debating chamber, designed for adversarial and noisy politics, is out of fashion and increasingly out of use, though immensely popular when it does engage in a debate of major importance nowadays, often on social issues – gay marriage or the right to die. Though David Cameron echoes Tony Blair's excuse that he gives frequent statements on which MPs can challenge him it's not the same as a debate on a substantive motion.

In my youth, Jim Callaghan's government fell on such a motion – "that this House has no confidence in… " as moved by Margaret Thatcher. Yet I cannot remember such a debate since 18 March 2003, the great drama opened by the then prime minister, Tony Blair, who carried the day (on Tory votes against a major Labour revolt) to join British troops in the ill-starred US invasion of Iraq.

That's a loss, I'd say. But it's in danger of getting worse. Acting on the landslide mandate voters had given him, Blair arbitrarily reformed PMQs in a way Thatcher – credit where it is due – would never have countenanced. He took the two 15-minute sessions on Tuesdays and Thursdays at 3.15pm and bundled them into one 30-minute session at noon on Wednesdays.

You can spot the sleight of hand. Twice 15 is 30, but two into one day means a 50% cut in the days on which a PM is answerable to MPs. Cameron is quietly in the process of cutting that further. He took a cue from Gordon Brown in gently letting slip his monthly Downing Street press conferences, a modest Blair innovation that is suited to the 24/7 TV age. As a pack, reporters are even worse than MPs at co-operating to achieve a better result.

But opposition MPs have also detected a marked Cameron tendency to avoid a Wednesday session of PMQs if he can. The device used – as it will probably be used next week – is to prorogue the House for a new session or rise for a seasonal break on a Tuesday instead of a Thursday. My thanks to the tireless blogger Paul Waugh of PoliticsHome, for setting this out in even starker terms than I had noticed.

Yes, the last PMQs was on budget day, 20 March, and the next will be this Wednesday, 24 April. What with holidays, the Queen's speech debate, Lady T's funeral, there will not be another one until 15 May – the last before June. In other words, more than two months will have passed with only two such sessions – 30 minutes a month, not 30 a week.

That's pretty shocking. Why so? It's not that Ed Miliband is a Blair or Harold Wilson, the opposition leader who regularly puts the PM through the mincer (as Thatcher rarely did wily old Callaghan, by the way); as my regular critics know, I think Cameron usually wins – as PMs should with Whitehall's armoury at his/her disposal.

The problem is, I suspect, that Cameron is often insufficiently on top of the detail and makes mistakes, tends to get flustered and to say things he regrets in the heat of that dreadful bear pit. "I know I shouldn't do it, but I can't help it, he's so annoying," Cameron was once overheard saying in a corridor after rising to Ed Balls's taunts.

Far more troubling surely than Balls's jeers is the insubordinate mood on Cameron's own side. He has a bad habit of referring to Tory questioners as "the Hon Gentleman/Lady"instead of "My Hon Friend". Hansard corrects the discourtesy but as a Freudian slip it shows. Disgruntled and anxious about the coming election they are increasingly bolder in their challenges. Lucky for Cameron that there is no Thatcher waiting in the wings. But, of course, that's what Ted Heath's acolytes used to tell each other in 1975.